71.3 Injuries of the brachial plexus

If an injured patient has a totally paralysed insensitive arm, he has a brachial plexus injury in which he has injured all three cords of his brachial plexus. He can also injure them separately. These injuries can be the result of falling from a tree, or from a motor cycle, as in Fig. 51-6. If a patient is lucky, he merely stretches his nerve roots, if he is unlucky he pulls them away from his cord. In both types of injury he loses the power and feeling in his arm, but in a stretch injury, he can usually still move his rhomboid muscles, because the nerve which supplies them leaves the brachial plexus close to the cord. In an avulsion injury, this nerve is torn from his cord with the rest of his brachial plexus, so that his rhomboid muscles no longer function on the injured side.

BRACHIAL PLEXUS INJURY Ask the patient to pull his shoulder blades together. If he can do this, the function of his rhomboids is intact.

If his rhomboids are intact, support his arm in a sling, protect it from injuries, such as cuts, bruises, and burns, until its sensation returns. Make sure that one of his relatives exercises his shoulder, elbow, and hand for 6 months or longer, because his arm may continue to recover for at least a year.

If his rhomboids are paralysed, he has probably torn the roots of his brachial plexus away from his cord, so that his injury is permanent. If he shows no signs of recovery at 6 months, consider amputating his upper arm through skin which has sensation.